1. Field of the Invention
The present invention generally relates to a structure and a fabricating method of a light source. More particularly, the present invention relates to a package structure and a package process of light emitting diode (LED).
2. Description of Related Art
Light emitting diodes (LEDs) have replaced fluorescent lamps and incandescent lamps in some fields, for example, lamps of scanners requiring for quick response, lamps of projection apparatus, backlight sources or front light sources of liquid crystal displays (LCDs), illumination for dashboards of automobiles, traffic lights, common illumination devices, etc. Compared with conventional lamps, the LEDs have absolute advantages, for example, small volume, long lifespan, low driving voltage/current, non-fragile, mercury free (no pollution), and good luminous efficiency (power saving).
FIG. 1 is a cross-sectional view showing a conventional white LED package structure. As shown in FIG. 1, in the conventional white LED package structure 100, an LED chip 110 is bonded to a bottom surface 122a of a cavity 122 of a carrier 120. A part of lights 152 emitted from the LED chip 110 is converted via phosphor particles 130 distributed in a resin 140, so as to output white lights 154. However, chromatic aberration (e.g. yellowish) occurs since the lengths of light paths (e.g. L1, L2) in the resin 140 corresponding to different emergence angles (e.g. θ1, θ2) from the LED chip 110 are varied. Accordingly, luminance of the white LED package structure 100 is reduced, and color of the light output is not uniform.
Besides, the prior art further provides another LED package structure having a phosphor coating layer formed by wafer level fabrication, wherein the phosphor coating layer conformally and fully covers the LED chip and the carrier so as to output a uniform white light. Nonetheless, the fabrication cost of the phosphor coating layer goes high due to performing a wafer level coating process.